Amounts of phosphate (as the measure of phospholipids) and cholesterol determined by biochemical assays in the organic extracts of detergent-treated boar spermatozoa. From these data, the ratio between cholesterol and phosphate (C/P) was also calculated. Sperm cells were incubated with detergents for 30 min at 4°C and lipids were extracted and determined as described in the Materials and Methods section. The mean ± SD of two different extractions per sample is shown. Please note that there are only slight differences between the individual detergents.